Two-dimensional picture frame



FIG. 1 is a top plan view of a picture frame, showing my new design;

FIG. 2 is a front elevational view, the rear being identical thereto;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a side elevational view, the opposite side being identical thereto. 

The ornamental design for a picture frame, as shown and described. 